In the interwar period, sports gained considerable popularity. Stadiums, gymnasiums, and a number of swimming pools were built in the city. One of them was the outdoor pool Żelazna Woda (Iron Water), which was built in 1933-1938 according to the project designed by Adam Kozakiewicz and Leopold Karasiński in the place of the former pond of the Kamiński family. Today, it functions as the swimming pool Dynamo on Stusa street near Zalizna voda park. The construction was carried out at the expense of the city community, the Labor Fund's subsidy and, partly, the communal fund; its cost was 201,000 zlotys.

The complex was designed for 2,000 persons; two bowls were arranged, a shallow one for children, with a size of 30 x 60 m; and a deeper one for adults, with a size of 18 x 50 m. The latter's depth reached 3.5 m near the springboard. The total area of ​​the two pools reached 3,000 m². Near the concrete bowls, there are cloakrooms and showers where visitors washed themselves before bathing.

In 1932-33, an underground tank was constructed to collect water from the stream of Sofiyivka which was filled from the so-called Röring springs (at the foot of the park hills) and Jankowski (at Snopkiv), at a speed of 15-18 thousand l/h. Regeneration of water in the pool took 8-10 days. In 1938 the complex was equipped with a special filter to catch particles of iron, too abundant in water from the park Zalizna Voda. The water in the pool was completely replaced approximately every 20 days. It was done on aesthetic reasons, because the pool's bottom was gradually overgrown with algae and, as a result, the water went cloudy.